hlh0501

iTrader: (1)

This is one area I do not know well enough yet

which is why I ask..

I know some other people have problems with cracking manifolds, I've seen it happen a few times in person. It is usually aftermarket turbo manifolds though, or custom tubular ones.

I doubt there is a yes/no answer to this, but just curious if anyone has looked into this at all, and have any info on our stock manifolds?

Thanks for any help

mzmtg

iTrader: (11)

No idea, but I heard that too much naws will kill your radiator...

Mishap

Hahahahaha

On to the question. Exactly what is antilag? Kind of a vague term.

I've seen and heard of quite a few aftermarket manifolds crack. But almost all of them were tubular ones, not cast iron ones. And they were not braced properly. You hang a 20-25 lb turbo on some steel pipes and eventually it's going to crack from vibration/fatigue/and just general movement from driving. I haven't seen too many manifolds with braces crack. On my girlfriend's car, we have a tubular stainless steel manifold that's braced. Absolutely no problems. I've seen people running the same manifold without the bracing crack in 2-3 months.

Bottom line is with proper design, it really shouldn't crack.

Mishap

BTW, that was Shadow...I was using his computer earlier.

hlh0501

iTrader: (1)

mzmtg, whats your point? I guess I could go the makes no power route since it has proven reliable by yourself... but that would be no fun.


mishap/shadow:
antilag, I am still a hair unclear on myself. there are a few methods of it, but basically the goal is to make full boost while the car is under no load.

the first step to making boost would be a two step, just having a low rev limiter, but antilag takes it another step - and can skyrocket your boost, just sitting still. the point being, so you can leave the line under full power/boost. you can also have it during shifts etc, so you are always making boost.

it has been explained to me a few ways, and I tried to read on it. it produces a large amount of hot high velocity exhaust gas, which keeps the turbo going. now how it does that, I have heard a few different reasons - most recently I was told by an autronic owner that it moves ~50% of the combustion, after the cylinder - before the turbo.

many of my friends locally use autronic, and the antilag feature combined with twostepping is AWESOME on the launches,etc. but they also have a way of breaking things doing so, mainly manifolds - although autronic recommends egt on the turbo itself too to make sure you dont burn up the turbo and watching to make sure of no valve damage. it's pretty mean stuff, but I am thinking with our stock cast manifolds... they would be ok?

VIDEO of friends silvia w/ antilag
you can hear the turbo spool and lots of popping, etc before he drops the clutch to warmup his tires. he makes ~18psi just in neutral.

Mishap

Oh, I know what you're talking about now. You're thinking about those systems that dump excess fuel into the engine off throttle which causes them to burn in the manifold to keep the turbo spooling. It's popular in WRC but those systems have a much better engine control system and beefier manifolds. Doing that in your car is gonna make a mess and it's not worth the cost/damage to the car should something go wrong. Unless your car is a complete dog off boost, it's pretty pointless especially on a car that isn't doing a lot of speed changes, ie road racing where low RPM response is critical.

Also, what's the reason for running such a system when nitrous pretty much does the same thing w/o the stress of combustion going on in the manifolds. Also rally cars sound like hell off throttle w/ their weird burping and popping b/c of the system. A properly sized turbo or small nitrous system should be more than enough to give a car reasonable response w/o something as intensive as that.

Think about fuel inside the manifold after the engine in your glowing hot manifolds...can be unpredictable w/ how long the manifolds on turbo setups for the Max can be. It may not light right away and build up until it blows something up. May be ok in the manifold but not in the several feet of pipe leading from the banks. Just stick w/ the nitrous unless you're running in a class that doesn't allow it.

stephenlc

iTrader: (1)

Wow, sounds interesting but never heard of it before. If you did not properly tune that you could have major headaches, but 10psi off the line sounds great! I agree with Mishap that nitrous would help the turbos spool off the line and you would not need to do that.

DA-MAX

iTrader: (10)

I've seen this used a few weeks ago on a Zdyne equppied CRX...its the same as "full throttle launch" on boosted cars pretty much. it took a few dyno runs to perfect but the key is to retard timing and dump fuel at the selected launch RPM(as was probably already stated in the above) not sure how it would be done on a Maxima...MSD two step, an AFC and J&S all together maybe I have this option on my Uberdata equipped ECU in my Teg, but I'm scared as all hell to use it

on_alert

in essence, the way antilag works is destructive. It is not only rough on the manifold, but also your engine, because it the gas pings in the cylinder.

I alsways wondered if you could inject propane into the turbo housing tho... That would be dope...

DA-MAX

iTrader: (10)

can someone break down propane injection...I have no clue how it works? similar to nitrous?? all I know is that on Trucks last week they installed the Bullydog propane injection and N20 unit on a turbo diesel Ram and that focker gained like 200+ hp and some ungodly amount of torque

stephenlc

iTrader: (1)

Propane is like really high propane gas, only works with diesal fuel I think.

luckee2bhere

iTrader: (1)

Shadow

iTrader: (15)

My friend runs propane on his Supra. I think on his, it's sprayed similarly to the nitrous setup (he runs that too). It really doesn't add that much power, it just reduces combustion temps a lot. He runs higher boost with the propane. At least that's how he explained it to me.

IceY2K1

iTrader: (3)

Rally car antilag ECU programs retard the timing as the driver lets off the throttle and then dumps excess fuel which ignites from the heat of the manifold/turbine vs. a spark plug thus causing a mild/wild explosion, which then quickly spools the turbine. Don't try this with catalytic convertors on street cars please.

In WRC it's used to keep the turbo at max boost when the driver lets off, so when he gets back into the throttle he's got peak boost.

In tractor pulls, they inject fuel/nitro-meth or whatever with aux injectors DIRECTLY into the turbine, which explodes forcing the HUGE azz turbine to spool faster.

IceY2K1

iTrader: (3)

Rally car antilag ECU programs retard the timing as the driver lets off the throttle and then dumps excess fuel which ignites from the heat of the manifold/turbine vs. a spark plug thus causing a mild/wild explosion, which then quickly spools the turbine. Don't try this with catalytic convertors on street cars please.

In WRC it's used to keep the turbo at max boost when the driver lets off, so when he gets back into the throttle he's got peak boost.

In tractor pulls, they inject fuel/nitro-meth or whatever with aux injectors DIRECTLY into the turbine, which explodes forcing the HUGE azz turbine to spool faster.

on_alert

so you can inject right into the turbo housing! Is it detrimental tho?

IceY2K1

iTrader: (3)

I'd say so. However, they are making turbine wheels out of very tough materials to withstand the heat like Inconel(sp?), Mar-mar(sp?), etc, but I can't imagine the "shock" from the gas igniting doesn't cause damage over time, sort of like detonation.

Rally car turbines seem to handle anti-lag fine though. It just gets black as hell. I'm still learning about what goes on with the ECUs, but that's the jist of what I've seen/heard.

I think for the street, N20 is the best "anti-lag".